RE: [PATCH v5 5/7] drm/aspeed: Add reset and clock for AST2600

Tommy Huang
2022-03-01T07:00:33Z

Hi Joel,

It seems that the reset control could keep original code behavior.
Just change the reset define in the .dtsi file from ASPEED_RESET_CRT1 into ASPEED_RESET_GRAPHICS.

By the way, the HW controller states and FW programming register will be reset by CRT reset line.
And another part HW controller states will be reset by engine reset line.

Thanks,

By Tommy

> -----Original Message-----
> From: Joel Stanley <joel@jms.id.au>
> Sent: Monday, February 28, 2022 5:51 PM
> To: Tommy Huang <tommy_huang@aspeedtech.com>
> Cc: David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Rob
> Herring <robh+dt@kernel.org>; Andrew Jeffery <andrew@aj.id.au>;
> linux-aspeed <linux-aspeed@lists.ozlabs.org>; open list:DRM DRIVERS
> <dri-devel@lists.freedesktop.org>; devicetree <devicetree@vger.kernel.org>;
> Linux ARM <linux-arm-kernel@lists.infradead.org>; Linux Kernel Mailing List
> <linux-kernel@vger.kernel.org>; BMC-SW <BMC-SW@aspeedtech.com>
> Subject: Re: [PATCH v5 5/7] drm/aspeed: Add reset and clock for AST2600
>
> On Wed, 8 Dec 2021 at 01:34, Tommy Haung
> <tommy_huang@aspeedtech.com> wrote:
> >
> > From: tommy-huang <tommy_huang@aspeedtech.com>
> >
> > Add more reset and clock select code for AST2600.
> > The gfx_flags parameter was added for chip caps idenified.
>
> Can you tell me a bit more about the two reset lines:
>
> What is the CRT reset line controlling?
>
> What does the engine reset line control?
>
> Can we use devm_reset_control_array_get() to get whichever are specified in
> the device tree, so we don't need to have different logic for the 2600 and
> earlier chips?
>
>
>
> >
> > Signed-off-by: tommy-huang <tommy_huang@aspeedtech.com>
> > ---
> > drivers/gpu/drm/aspeed/aspeed_gfx.h | 16 +++++++-
> > drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c | 16 ++++++++
> > drivers/gpu/drm/aspeed/aspeed_gfx_drv.c | 50
> ++++++++++++++++++++++--
> > 3 files changed, 77 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > index 4e6a442c3886..2c733225d3c7 100644
> > --- a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > @@ -8,7 +8,8 @@ struct aspeed_gfx {
> > struct drm_device drm;
> > void __iomem *base;
> > struct clk *clk;
> > - struct reset_control *rst;
> > + struct reset_control *rst_crt;
> > + struct reset_control *rst_engine;
> > struct regmap *scu;
> >
> > u32 dac_reg;
> > @@ -16,6 +17,7 @@ struct aspeed_gfx {
> > u32 vga_scratch_reg;
> > u32 throd_val;
> > u32 scan_line_max;
> > + u32 flags;
> >
> > struct drm_simple_display_pipe pipe;
> > struct drm_connector connector;
> > @@ -106,3 +108,15 @@ int aspeed_gfx_create_output(struct drm_device
> > *drm);
> > /* CRT_THROD */
> > #define CRT_THROD_LOW(x) (x)
> > #define CRT_THROD_HIGH(x) ((x) << 8)
> > +
> > +/* SCU control */
> > +#define SCU_G6_CLK_COURCE 0x300
> > +
> > +/* GFX FLAGS */
> > +#define RESET_MASK BIT(0)
> > +#define RESET_G6 BIT(0)
> > +#define CLK_MASK BIT(4)
> > +#define CLK_G6 BIT(4)
> > +
> > +#define G6_CLK_MASK (BIT(8) | BIT(9) | BIT(10))
> > +#define G6_USB_40_CLK BIT(9)
> > diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > index 827e62c1daba..e0975ecda92d 100644
> > --- a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > @@ -77,6 +77,18 @@ static void aspeed_gfx_disable_controller(struct
> aspeed_gfx *priv)
> > regmap_update_bits(priv->scu, priv->dac_reg, BIT(16), 0); }
> >
> > +static void aspeed_gfx_set_clk(struct aspeed_gfx *priv) {
> > + switch (priv->flags & CLK_MASK) {
> > + case CLK_G6:
> > + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE,
> G6_CLK_MASK, 0x0);
> > + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE,
> G6_CLK_MASK, G6_USB_40_CLK);
> > + break;
> > + default:
> > + break;
> > + }
> > +}
> > +
> > static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv) {
> > struct drm_display_mode *m =
> > &priv->pipe.crtc.state->adjusted_mode;
> > @@ -87,6 +99,8 @@ static void aspeed_gfx_crtc_mode_set_nofb(struct
> aspeed_gfx *priv)
> > if (err)
> > return;
> >
> > + aspeed_gfx_set_clk(priv);
> > +
> > #if 0
> > /* TODO: we have only been able to test with the 40MHz USB
> clock. The
> > * clock is fixed, so we cannot adjust it here. */ @@ -193,6
> > +207,7 @@ static void aspeed_gfx_pipe_update(struct
> > drm_simple_display_pipe *pipe, static int
> > aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe) {
> > struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> > +
> > u32 reg = readl(priv->base + CRT_CTRL1);
> >
> > /* Clear pending VBLANK IRQ */ @@ -207,6 +222,7 @@ static int
> > aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe) static
> > void aspeed_gfx_disable_vblank(struct drm_simple_display_pipe *pipe)
> > {
> > struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> > +
> > u32 reg = readl(priv->base + CRT_CTRL1);
> >
> > reg &= ~CRT_CTRL_VERTICAL_INTR_EN; diff --git
> > a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > index d10246b1d1c2..59a0de92650f 100644
> > --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > @@ -64,6 +64,7 @@ struct aspeed_gfx_config {
> > u32 vga_scratch_reg; /* VGA scratch register in SCU */
> > u32 throd_val; /* Default Threshold Seting */
> > u32 scan_line_max; /* Max memory size of one scan line */
> > + u32 gfx_flags; /* Flags for gfx chip caps */
> > };
> >
> > static const struct aspeed_gfx_config ast2400_config = { @@ -72,6
> > +73,7 @@ static const struct aspeed_gfx_config ast2400_config = {
> > .vga_scratch_reg = 0x50,
> > .throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
> > .scan_line_max = 64,
> > + .gfx_flags = 0,
> > };
> >
> > static const struct aspeed_gfx_config ast2500_config = { @@ -80,6
> > +82,7 @@ static const struct aspeed_gfx_config ast2500_config = {
> > .vga_scratch_reg = 0x50,
> > .throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
> > .scan_line_max = 128,
> > + .gfx_flags = 0,
> > };
> >
> > static const struct aspeed_gfx_config ast2600_config = { @@ -88,6
> > +91,7 @@ static const struct aspeed_gfx_config ast2600_config = {
> > .vga_scratch_reg = 0x50,
> > .throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
> > .scan_line_max = 128,
> > + .gfx_flags = RESET_G6 | CLK_G6,
> > };
> >
> > static const struct of_device_id aspeed_gfx_match[] = { @@ -138,6
> > +142,44 @@ static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
> > return IRQ_NONE;
> > }
> >
> > +static int aspeed_gfx_reset(struct drm_device *drm) {
> > + struct platform_device *pdev = to_platform_device(drm->dev);
> > + struct aspeed_gfx *priv = to_aspeed_gfx(drm);
> > +
> > + switch (priv->flags & RESET_MASK) {
> > + case RESET_G6:
> > + priv->rst_crt = devm_reset_control_get(&pdev->dev,
> "crt");
> > + if (IS_ERR(priv->rst_crt)) {
> > + dev_err(&pdev->dev,
> > + "missing or invalid crt reset controller
> device tree entry");
> > + return PTR_ERR(priv->rst_crt);
> > + }
> > + reset_control_deassert(priv->rst_crt);
> > +
> > + priv->rst_engine = devm_reset_control_get(&pdev->dev,
> "engine");
> > + if (IS_ERR(priv->rst_engine)) {
> > + dev_err(&pdev->dev,
> > + "missing or invalid engine reset
> controller device tree entry");
> > + return PTR_ERR(priv->rst_engine);
> > + }
> > + reset_control_deassert(priv->rst_engine);
> > + break;
> > +
> > + default:
> > + priv->rst_crt =
> devm_reset_control_get_exclusive(&pdev->dev, NULL);
> > + if (IS_ERR(priv->rst_crt)) {
> > + dev_err(&pdev->dev,
> > + "missing or invalid reset controller
> device tree entry");
> > + return PTR_ERR(priv->rst_crt);
> > + }
> > + reset_control_deassert(priv->rst_crt);
> > + break;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int aspeed_gfx_load(struct drm_device *drm) {
> > struct platform_device *pdev = to_platform_device(drm->dev);
> > @@ -163,6 +205,7 @@ static int aspeed_gfx_load(struct drm_device *drm)
> > priv->vga_scratch_reg = config->vga_scratch_reg;
> > priv->throd_val = config->throd_val;
> > priv->scan_line_max = config->scan_line_max;
> > + priv->flags = config->gfx_flags;
> >
> > priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
> > if (IS_ERR(priv->scu)) {
> > @@ -186,13 +229,12 @@ static int aspeed_gfx_load(struct drm_device
> *drm)
> > return ret;
> > }
> >
> > - priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> > - if (IS_ERR(priv->rst)) {
> > + ret = aspeed_gfx_reset(drm);
> > + if (ret) {
> > dev_err(&pdev->dev,
> > "missing or invalid reset controller device tree
> entry");
> > - return PTR_ERR(priv->rst);
> > + return ret;
> > }
> > - reset_control_deassert(priv->rst);
> >
> > priv->clk = devm_clk_get(drm->dev, NULL);
> > if (IS_ERR(priv->clk)) {
> > --
> > 2.17.1
> >